EP0203904A1 - Shuttering and armouring wall - Google Patents

Abstract

The invention relates to the construction of tunnels. It has for its object a formwork and shielding wall, constituted by the end-to-end assembly of sections (1) each constituted by at least two parts (2, 3, 4, 5) of section assembled together end to end, the ends facing each other being connected by a key (6). Each section portion consists of a number of elements hinged together. The key has two lateral insertion surfaces and the end elements adjacent to it are provided with assembly means compatible with these insertion surfaces. The formwork wall according to the invention has the advantage of being made up of elements adaptable to any form of tunnel and recoverable after use, is easy to handle, allows the transmission of longitudinal and transverse forces caused by the advancement of the shield. the drilling machine and pouring concrete and does not require the use of a formwork skin.

Description

The present invention relates to a wall for producing formwork for pouring concrete in place for making sails, slabs and vaults (tunnel) and also intended for armouring floors, that is to say for contain the earth when digging trenches or other earthworks.

The present invention will be described below with reference to its preferred application which is the production of formwork for the execution of tunnel coatings of concrete poured in place, and, more particularly, in the case of tunnels made in underground excavations.

The execution of tunnels of this type, with concrete coating poured in place, is well known and consists in digging a tunnel section, generally by means of a drilling machine, and in carrying out the coating by pumping fresh concrete into the free space between the shield of the machine which advances in the direction of drilling and the fitted formwork. The shield is propelled in the direction of piercing generally by means of thrust cylinders acting parallel to the axis of the tunnel. These generally rest on the lining of the already sunk tunnel.

However, in practice, the coating is carried out at the same work rate as the tunneling, by pumping fresh concrete into the free space between the machine shield and the concrete already poured and which is hardening, maintained by the fitted formwork.

It is therefore not possible to lean on the freshly poured concrete until it has reached a given resistance, which represents a waste of time for the advancement of the work.

To avoid this loss of time, it is advantageous for the advancement cylinders to rest on the lining of the tunnel through the fitted formwork. The longitudinal forces of propulsion of the shield thus pass by friction between said formwork and the concrete in the lining of the tunnel, which makes it possible to work with a finite length of formwork, the formwork being able to be dismantled when the concrete is hard.

An exemplary method and machine for the continuous execution of a tunnel lining in concrete poured in place and compressed is described in Belgian Patent ^No. 838,048.

The formwork for the production of a poured concrete covering must obviously follow the internal profile of the tunnel to be produced, a gap being however created between the external surface of the formwork (the formwork surface) and the excavated earth.

The tunnels have either a polygonal, and in particular rectangular section, or, more generally, a section comprising arcuate, and in particular circular, parts, corresponding to the roof of the tunnel, for example.

The formwork for the realization of a tunnel lining generally consists of sections assembled end to end. Each of these formwork sections therefore comprises at least one arcuate part corresponding, for example, to the roof of the tunnel.

On the other hand, each section consists of at least two parts assembled end to end in a rigid or articulated manner so that the joining edges are parallel to the axis of the section (and of the tunnel), in order to facilitate its transport and all placement operations inside the tunnel. One of these parts therefore at least comprises a curved portion.

In known manner, the parties which constitute the sections of formwork are made of cast iron, steel or concrete. These parts are, therefore, heavy and bulky, therefore difficult to handle and have a fixed arcuate shape and cannot be modified.

The use of this type of formwork is therefore limited to tunnels having a very precise cross-section; in particular, the arcuate section portions according to a determined radius of curvature can only be suitable for tunnels having vaults of the same transverse radius of curvature.

This type of formwork is therefore not compatible with arbitrary and modifiable shapes, whether this is in the course of the same tunnel with variable section, or for tunnels having different sections and profiles.

We also know sections of formwork made of wooden or metal beams arranged parallel to the axis of the tunnel and fixed to a flexible outer sheet having a smooth surface against which the concrete will be poured (formwork surface), wood, multiplex, steel or aluminum, made up of curved or flexible panels, or of narrow width adjoining elements. Transversal tie rods connect the beams to each other and ensure the transverse rigidity of the assembly.

The use of this type of formwork to make a tunnel coating of poured concrete however requires the presence of a support frame, mounted inside each section of the formwork, because the outer sheet alone does not allow take up the transverse compression forces created by the pouring of the concrete under pressure, since it must be thin and flexible enough to match a desired curvature.

Furthermore, this type of formwork cannot be used for the realization of a concrete covering, poured at the same working rate as the drilling.

In fact, the construction of this type of formwork does not allow the propulsion forces of the shield to be transmitted to the covering by friction between the formwork and the concrete, since the fixing of the longitudinal beams (on which the advancement jacks should rest shield) to the outer sheet (formwork surface in contact with concrete), will not resist shear forces.

Inflatable forms are also known which consist of a cylindrical envelope of rubber reinforced with synthetic fibers, into which air is injected under pressure and around which the concrete is poured.

As soon as the concrete is sufficiently hard, the air is evacuated from the envelope, and the latter is extracted along the axis of the pipe.

Inflatable formwork is however limited to the production of cylindrical pipes whose diameter does not exceed 3 meters. In addition, the presence of a synthetic fiber reinforcement does not allow to vary significantly the diameter of a formwork of this type, each envelope can only be used for a determined diameter of pipe. Finally, the presence of the inflatable envelope therein, as long as the concrete is not sufficiently hard, prevents any activity in the pipe, and in particular the continued digging. It should also be noted that the inflatable forms are preferably used in open trenches, the concrete being poured from the outside, between the excavated soil and the surface of the envelope and are used above all to make sections of relatively long lengths. important (up to 30 meters), but of relatively small sections, for example sewer pipes, etc.

The object of the present invention is a formwork and shielding wall which is easy to handle and place, which, while allowing the transmission of the compressive, tensile and shear forces, both transverse and longitudinal, caused by the advancement of the shield. the drilling machine and by pouring and setting the concrete is constructed from a maximum of standard recoverable elements which can be used repeatedly, does not require the use of an additional formwork skin and can be adapt to all desired shapes, and to all dimensions of tunnels, by varying the number of standard elements used.

To this end, the standard elements are relatively small in size and weight, and can therefore be easily manipulated by the force of the arms and therefore without the use of lifting devices, etc.

The configuration of these standard elements, as well as their method of assembly, allows the transmission of various stresses, both longitudinal and transverse, such as, for example, the forces of propulsion of the shield of a machine for drilling tunnels, or the forces of compression. transverse driven by pouring concrete under pressure.

The possibility of varying the number of standard elements assembled makes it possible to precisely adjust the dimensions of the wall as required; thus, for example, the length of the perimeter of a section of formwork used for making the lining of a tunnel can be precisely adjusted to the interior dimensions of the tunnel, so as to obtain precisely the thickness of the lining desired.

In addition, the standard elements used are assembled in such a way that they mesh and produce by themselves a sufficiently smooth shuttering wall against which the concrete will be poured.

Finally, the assembly of standard elements is arranged so as to form an articulation around a current axis along the assembled edges of two contiguous elements, which allows a formwork wall made up of these elements to exactly match the curvature. cross section of the tunnel.

The present invention also allows the passage of fluid for heating and cooling the formwork wall, which makes it possible to accelerate or adjust the setting of the concrete.

The present invention relates to a formwork and shielding wall, constituted by the end-to-end assembly of sections by their end faces, each section comprising at least one arcuate part whose generatrix is parallel to the axis of the section. , each section being constituted by at least two sections of section assembled together end to end, so that the joining edges are parallel to the axis of the section, and by at least one key interposed between the surfaces of the ends of two sections of section facing each other. Each section portion is itself made up of a certain number of identical main elements and, at each of its ends, of an end element and of connection and blocking means. Each main element comprises a substantially rectangular formwork plate, one face of which forms the formwork surface, and a stiffening core spaced from the formwork plate and located on the side of the face opposite to the formwork surface and rigidly connected to the formwork plate; the plate is provided along two edges parallel to each other and to the axis of the section of means of junction with the edge of neighboring plates; these joining means constitute an articulation around an axis running along the assembled edges. Each end element also comprises a substantially rectangular formwork plate, one face of which forms the formwork surface, and a stiffening plate spaced from the formwork plate and located on the side of the face opposite to the formwork surface and connected by rigidly to the formwork plate by a core, each end element is attached to the formwork plate of the last main element of a section portion by a joining means, and, on the free end side, it is profiled, so as to allow connection and attachment with the end element; of a neighboring section portion, the connection and blocking means connect the cores and the stiffening plates so as to keep locked in a determined position, with respect to each other, all the elements of the same section portion ; the key also has a formwork surface and two lateral insertion surfaces and the end elements adjacent to the key are provided with means of assembly with the key and compatible with the lateral insertion surfaces of the latter, of so as to allow the insertion of the key with the formwork surface in front.

According to an advantageous embodiment, the joining means connecting the shuttering plates of the main elements together and with the shuttering elements of the end elements of the same portion of section comprise, on the one hand, a cylindrical node full and, on the other hand, the hollow cylindrical imprint of the same node, the assembly between plates of shuttering of two neighboring elements by interlocking a node of an element in the hollow imprint of a neighboring element, in a direction parallel to the axis of the section.

According to a preferred embodiment, the formwork plate of a main element carries, along one of two parallel edges, a solid cylindrical knot and, along the other edge, the hollow cylindrical footprint of the same node.

According to an advantageous embodiment, the stiffening core is connected to the formwork plate by means of two connecting elements arranged in a V, these can be either solid webs, or reticular structures.

The connecting elements and the stiffening core form an integral V-shaped structure.

According to a preferred embodiment, the formwork plate carries, on its face opposite to the formwork surface, two parallel ribs provided, along their free edge, with a solid cylindrical knot, and the free edge of each of connecting elements of the V-shaped integral structure is provided with a hollow imprint of said node, the nesting of said two nodes in said imprints thus allowing the assembly of a main element.

The formwork plate can be connected to the integral V-shaped structure either by welding or by gluing.

According to a preferred embodiment, the stiffening core has a longitudinal groove in the form of a groove, intended to receive a nut for fixing with the connecting and blocking elements which connect the different stiffening cores to one another.

The end elements are profiled so as to allow hooking between them in the direction towards the formwork surfaces, both along the edge of the formwork plate, and along the edge of the stiffening plate.

Preferably, for one of the end elements, the attachment means along the edge of the formwork plate consists of a rib provided with a flange, and the attachment means along the edge of the form plate stiffening consists of a notch, and for the other end element, the hooking means along the edge of the formwork plate consists of a notch intended to receive the edge of the first end element, and the means d 'hooking along the edge of the stiffening plate consists of a rib provided with a flange intended to be engaged in the notch of the first end element.

According to a preferred embodiment, each of the end elements consists of the same profile comprising two plates connected by a core perpendicular thereto, one of which constitutes the formwork plate and the other of which is assembled to a complementary connecting plate to constitute the stiffening plate; the two plates have, along their edges located on the side of the main element, one, a full longitudinal node and the other, the hollow imprint of the same node. The two plates have, in addition, along their edges on the side of the attachment of the elements to each other, one, a rib provided with a rim and the other, a notch; said profile thus allows indifferently, by turning it 180 °, both the assembly with a formwork plate of a main element having either an imprint or a knot, and the attachment of two end elements between them .

According to an advantageous embodiment, the key consists of a main element and two end elements, each carrying a plate, one face of which constitutes the sliding surface allowing the insertion of the key; each plate is connected to the nearest end element by an intermediate plate, one of the faces of which is provided with means for hooking to this end element.

On the other hand, the means for assembling the end elements with the key each consist of a plate, one face of which constitutes a sliding surface compatible with one of the sliding surfaces of the key, and of an intermediate plate. allowing attachment to the nearest end element.

The prefabricated elements used for the formwork wall according to the present invention can be made of various materials, metal, for example aluminum or its alloys, cast iron or steel, polymer materials reinforced or not, or fiber cement.

• la Fig. 1 est une coupe transversale schématique, à échelle réduite, d'un tronçon de coffrage assemblé;
• la Fig. 2 représente, à plus grande échelle, et avec arrachement partiel, la coupe d'une partie de tronçon;
• la Fig. 3 représente, à plus grande échelle, une coupe de la région de la clef, désignée par III dans la Fig. 1.
• la Fig. 4 est une section d'une forme d'exécution d'un élément principal;
• la Fig. 5 est une section d'une autre forme d'exécution d'un élément principal;
• la Fig. 6 est une section d'une autre forme d'exécution d'un élément principal;
• la Fig. 7 représente; à plus grande échelle, l'assemblage de deux parties de tronçon successives suivant la plan A de la Fig. 1;
• la Fig. 8 est une section d'un profilé constituant un élément d'extrémité;
• la Fig. 9 est une section de deux plaques de liaison constituant chacune un élément d'extrémité;
• la Fig. 10 est une coupe transversale, à plus grande échelle, de la région du tronçon comprenant la clef;
• la Fig. 11 est une section d'une plaque permettant l'insertion de la clef entre deux parties de tronçon;
• la Fig. 12 est une section d'une plaque intermédiaire assurant la liaison entre un élément d'extrémité et la plaque de la Fig. 11;
• la Fig. 13 est une section d'une plaque d'épaisseur permettant d'ajuster avec précision les longueurs des parties de tronçon et de la clef;
• la Fig. 14 est une vue en perspective avec arrachements partiels d'une partie de tronçon;
• la Fig. 15 est une coupe suivant l'axe de symétrie d'un élément principal montrant l'assemblage des parties de tronçon ainsi que la liaison entre deux tronçons de paroi assemblés bout à bout;
• la Fig. 16 est une coupe, suivant un plan passant entre deux éléments principaux voisins, de l'assemblage de deux tronçons assemblés bout à bout.
• La Fig. 1 est une coupe transversale schématique, à échelle réduite, d'un tronçon de coffrage désigné dans son- ensemble par 1, et constitué par l'assemblage bout à bout, suivant le contour du tronçon 1, de parties de tronçon 2, 3, 4 et 5 et d'une clef 6, qui est intercalée entre les parties de tronçon 2 et 5. Pour la facilité de la description, le tronçon 1 représenté a une section circulaire, mais il va de soi que la présente invention peut s'adapter à des sections de tunnel quelconques.

The present invention will be described below in its preferred application which consists in the production of a tunnel lining, and more particularly a tunnel of circular section, with reference to the appended figures, among which:

• Fig. 1 is a schematic cross-section, on a reduced scale, of a section of assembled formwork;
• Fig. 2 shows, on a larger scale, and with partial cutaway, the section of a section portion;
• Fig. 3 represents, on a larger scale, a section of the region of the key, designated by III in FIG. 1.
• Fig. 4 is a section of a form of exe cution of a main element;
• Fig. 5 is a section of another embodiment of a main element;
• Fig. 6 is a section of another embodiment of a main element;
• Fig. 7 represents; on a larger scale, the assembly of two successive section parts along the plane A of FIG. 1;
• Fig. 8 is a section of a profile constituting an end element;
• Fig. 9 is a section of two connecting plates each constituting an end element;
• Fig. 10 is a cross section, on a larger scale, of the region of the section comprising the key;
• Fig. 11 is a section of a plate allowing the insertion of the key between two section parts;
• Fig. 12 is a section of an intermediate plate ensuring the connection between an end element and the plate of FIG. 11;
• Fig. 13 is a section of a thickness plate making it possible to precisely adjust the lengths of the section portions and of the key;
• Fig. 14 is a perspective view with partial cutaway of a section portion;
• Fig. 15 is a section along the axis of symmetry of a main element showing the assembly of the section parts as well as the connection between two wall sections assembled end to end;
• Fig. 16 is a section along a plane passing between two neighboring main elements, of the assembly of two sections assembled end to end.
• Fig. 1 is a schematic cross section, on a reduced scale, of a section of formwork designated as a whole by 1, and constituted by the end-to-end assembly, along the contour of the section 1, of section parts 2, 3, 4 and 5 and of a key 6, which is interposed between the parts of section 2 and 5. For ease of description, the section 1 shown has a circular section, but it goes without saying that the present invention can be adapted to any tunnel section.

The section portions 2, 3, 4 and 5 are assembled together along planes A, B and C parallel to the axis of the section and passing through this axis. The key 6 is interposed between the ends facing the section portions 2 and 5 to complete the circumference of the formwork wall, along planes D and E which are parallel to each other or even, at the limit, slightly convergent of the inside towards the outside of the tunnel, as illustrated, in order to facilitate the insertion of the key 6 and the blocking in place of the formwork 1.

The formwork section 1 has a continuous formwork surface 13, against which the concrete covering will be poured.

Fig. 2 represents, on a larger scale, the section, with partial cutaway, of a portion of section 3 (or 4, the parts-3 and 4 being identical), constituted by the edge-to-edge assembly of a certain number of main elements 7 and having an end element 8 at one end, and an end element 9 at the other, these end elements 8 and 9 allowing assembly with the nearest end element 8, 9 of a portion of neighboring section. Each element 7 comprises a plate 14, the edges of which are parallel to the axis of the section are provided with joining means allowing articulation with neighboring elements. These joining means comprise a knot full cylindrical 15 of an edge of a plate 14 which fits perfectly into the hollow imprint 16 of an adjacent plate 14 forming a hinge around a current axis along the assembled edges. The end elements 8 or 9 fit in the same way at the edges of the plates 14. To assemble the elements 7 with each other or with the end elements 8 or 9, a full knot 15 is threaded into a recess 16 The different elements 7, 8 and 9 are rigidly joined together by connecting and blocking means 10, as will be described below.

One can assemble a whole section portion, for example 2, by positioning the elements 7 on a template having the shape of the future formwork surface; the elements 7 are fitted together, the end elements 8 and 9 are then threaded at each end and the whole is fixed by the connection and blocking means 10.

Fig. 3 shows, in cross section, the region of the section 1 comprising the key 6, and designated by III in FIG. 1, and in which the ends situated opposite one another of the section portions 2 and 5 are illustrated, as well as the key 6 (for greater clarity, this is shown away from its position insertion). The illustrated ends of the section portions 2 and 5 are provided with assembly means 11 and 12 with the key 6, respectively, allowing the insertion of the key 6.

Fig. 4 represents, on a larger scale, the section of a main element 7.

The element 7 further comprises a stiffening core 17 of rectangular section and offset towards the inside of the tunnel, relative to said plate 14. The stiffening core 17 is connected to the plate 14 by webs 18, and ensures the rigidity of the element 7. In addition, the stiffening core 17 allows the assembly of the element 7 with the connecting and locking means 10, for example by welding or gluing , or bolting, as illustrated.

Fig. 5 shows the section of another embodiment of the main element. The identical parts have the same reference numbers as for the main element 7 in FIG. 4. The element 19 illustrated in FIG. 5 comprises a stiffening core 20 having a longitudinal groove 21 profiled and dimensioned to receive a nut of a screw (not shown) ensuring assembly with the connection and blocking means 10.

Fig. 6 shows the section of a third embodiment of the main element. The element 22 illustrated is composed, on the one hand, of a plate 23, and on the other hand, of a part designated as a whole by 24 and comprising a stiffening core 25 provided with a groove 21 and two sails 26; the plate 23 and the part 24 are rigidly assembled together by interlocking ribs having longitudinal nodes 27 secured to the plate 23 in the recesses 28 in the hollow of these nodes, located along the free edges of the sails 26.

Fig. 7 shows, in cross section and, on a larger scale, the assembly of the section parts 2 and 3 along the plane A of FIG. 1. These section portions 2 and 3 are assembled together by the respective end elements 9 and 8. On the formwork side, the end element 9 comprises a formwork plate 29, the formwork surface of which is substantially rectangular. One of the edges of this plate 29 is provided with a cylindrical knot 15 which fits into the recess 16 of the edge of the plate 23 neighbor. The other edge is provided with a hooking means. Similarly, the end element 8 comprises a formwork plate 30. One of its edges is provided with a recess 16 intended to receive the cylindrical node 15 from the edge of the adjacent plate 23. The other edge is provided with a hooking means compatible with the hooking means of the formwork plate 29 of the end element 9.

On the inside, the end element 9 comprises a substantially rectangular stiffening plate 31. One of the edges of this plate 31 bears against the stiffening core 25 of the neighboring main element 22. The other edge is provided with a hooking means. Likewise, the end element 8 comprises a substantially rectangular stiffening plate 32. One of the edges bears against the stiffening core 25 of the neighboring main element 22. The other edge is provided with an attachment means compatible with the attachment means of the stiffening plate 31 of the end element 9.

The hooking means of the formwork plates 29, 30 as well as the hooking means of the stiffening plates 31, 32 are arranged so as to allow the hooking of the end of the section portion 3 to that of the section 2 (already placed), from inside the tunnel to the excavated land.

As shown in FIG. 7, the end element 9 consists of a profile 33 assembled to a connection plate 34. Similarly, the end element 8 consists of an identical profile 33, but turned 180 °, assembled to a connecting plate 35.

Profile 33, of which FIG. 8 shows the section, consists of two plates 29 and 30 and a core 39. The plate 29 is provided, on one side, with a cylindrical knot 15 and, on the other, with a means hooking consisting of a rib 36 provided with a flange 37. The plate 30 is provided, on one side, with a hollow cylindrical imprint 16 and, on the other, with a hooking means consisting of a notch 38 complementary to the rim 37. The two attachment means are on the same side. The opposite external surfaces of the plates 29 and 30 are planar and parallel. The plate 29 is connected to the plate 30 by a core 39, perpendicular to these surfaces.

In Fig. 7, the profile 33 is part of the end element 9. It is oriented so as to fit the cylindrical node 15 of its plate 29 into the recess 16 of the main element 22 adjacent, and its plate 30 lodges in its hollow imprint 16 the cylindrical node 15 of the neighboring main element.

The plate 29 of the profile 33 constitutes the formwork plate 29 and the plate 30 of the profile 33, assembled with the connecting plate 34, constitutes the stiffening plate 31.

In the case of the end element 8, the profile 33, on the other hand, is turned 180 ° so as to present the hollow imprint 16 of its plate 30 opposite the cylindrical node 15 of the main element 22 neighbor, and its plate 29 which has a cylindrical node 15 is connected to the core 25 of the same main element 22 by a connecting plate 35 having a recessed imprint 16.

The plate 30 of the profile 33 constitutes, here, the formwork plate 30 and the plate 29 of the profile, assembled with the connection plate 35, constitutes the plate 32.

The connecting plates 34 and 35 are in fact obtained by cutting out a formwork plate 23. FIG. 9 represents the two connection plates 34 and 35, or we still notice the presence of the two assembly ribs 27 of the element 22 (see Fig. 6).

Fig. 10 is, in cross section and, on a larger scale, the assembly of the section parts .2 and 5 along planes D and E of FIG. 1. In fact, FIG. 10 is similar to FIG. 3 but, on a larger scale. It represents the mode of insertion of the key 6 between the ends of the section parts 2 and 5.

As already explained above, with respect to FIG. 7, the section parts 2, 3, 4 and 5 are hooked to each other, by first placing a section part, then an end of the following section part is hooked at its end, from the inside the tunnel towards the formwork surface and the excavated soil. On the other hand, the key 6, which constitutes the last element of the assembly of the formwork section, must be inserted between the opposite ends of the section parts 2 and 5, by its two ends at once, from the inside. from the tunnel to the excavated land, the formwork surface 40 forward.

For this, the ends of the section portions 2 and 5 between which the key 6 must be inserted have surfaces 41 and 42 respectively, capable of allowing the insertion of the key 6 from the interior of the tunnel to the excavated soil.

Likewise, the key 6 has at its ends surfaces 43 and 44 complementary to surfaces 41 and 42.

The insertion of the key 6 is done by the simultaneous sliding, on the one hand, of the surface 43 on the surface 41, and on the other hand, of the surface 44 on the surface 42, along planes D and E which are parallel to each other or converge from inside the tunnel towards the cleared lands.

In Fig. 10, the ends of the section portions 2 and 5 as well as the ends of the key 6 are provided with plates 45 arranged so that one of their large faces is in the junction plane D or E, and thus constitutes a surface of sliding 41, 42, 43, 44. This large face 46 (see Fig. 11) is bordered, on one side, by a rib 47 provided with a flange 48, and, on the other side, by a notch 49 representing the hollow imprint of the rim 48. The other large face 50 is flat.

The parts 45 of each of the two insertion planes D and E located one at the end of a section portion and the other at the opposite end of the key 6 (Fig. 10) are oriented so that their large faces 46 are opposite one another. They will thus constitute the pairs of sliding surfaces 41-43 and 42-44. The profiles of these large faces 46 are complementary and the flanges 48 engage in the notches 49 located opposite. The ribs 47 serve as stops for positioning the key 6 in its insertion position so that its formwork surface 40 is in line with the formwork surfaces 13 of the section portions 2 and 5.

The key 6 consists of a main element 22 and two end elements 8 and 9, assembled to the plate 23 of said main element by the junction means already described (cylindrical nodes 15 fitted into recesses 16) and connected to the core 25 of said main element by connection plates 34 and 35, a plate 51 welded to these at 52 and bolted to the core 25 connecting the whole rigidly.

The plates 45 are connected to the elements end 8 or 9 of the section portions 2 and 5 and of the key 6 by an intermediate plate 53 (see FIG. 12), which has on one side, a large flat face 54, and on the other, attachment means compatible with those of a part 8 or 9 (rib 36 provided with a flange 37 and notch 38).

The length of the circumference of the wall section 1 can be precisely adjusted to the dimensions of the tunnel, because, in addition to the possibility of adding or removing a main element 7, 19 or 22, the plate width of which represents a module base, it is possible to insert between a plate 45 and an intermediate plate 53 one or more thickness plates 55 (Fig. 13). In Fig. 10, thickness plates 55 have been inserted between all the plates 45 and 53, but it is obvious that one or more of these thickness plates 55 can be omitted.

The assembly of all of the plates 45, 53 and possibly of the thickness plates 55 to the end element 8 or 9 to which they are connected is carried out, as illustrated, by a countersunk screw 56 passing through them.

Finally, the key 6 is provided with seals 57 and sliding 58.

The seals 57 are housed in the notches 49 of the plates 45 of the key 6. These seals 57 are intended to prevent losses of laitance by infiltration towards the interior of the tunnel during concreting and avoid the formation of gravel nests or other local concrete defects. They also aim to protect the sliding surfaces 41, 42, 43 and 44 against fouling. These seals 57 can be made of rubber or another polymer having similar properties.

Furthermore, sliding joints 58 cover the sliding surfaces 43 and 44 of the key 6. These sliding joints 58 allow the entire section 1 to be removed, which after pouring the concrete, undergoes elastic shortening due to the pressure acting on its surface 13 of external formwork, which causes a stress in the joints between the key 6 and the adjacent section portions 2 and 5. The sliding joints 58 are constituted, for example, by an elastomer-Teflon plate, which ensures a good distribution of the pressures while giving a possibility of sliding against the sliding surfaces 41, 42 of the ends of the section parts 2 and 5.

Fig. 14 is a perspective view with partial cutaway of a portion of section, showing main elements 22 assembled edge to edge by the junction means allowing articulation between neighboring elements (cylindrical node 15 fitting into a recess 16) and rigidly joined together by the connection and blocking means 10. The latter consist of a perforated plate 59 curved according to the desired arch curvature and fixed at each end of the stiffening core 25 by a countersunk screw 60 and a nut 61 (see Fig. 15) housed in the groove 21.

Fig. 14 also shows an end element 8 connected to the plate 23 of the last main element 22 by the junction means already described (cylindrical node 15 fitting into a recess 16), and connected to the stiffening core 25 of the same main element 23 by a connecting plate 35.

The end of the perforated plate 59 is welded to the connection plate 35 at 62.

Each section 1 has, on either side, an end face- perpendicular to the formwork surface 13 and to the axis of the section. These end faces make it possible to transmit the longitudinal thrust forces caused by the advancement of the shield of the machine. These end faces are divided into arcs of length equal to those of the section parts.

The end face of a portion of section consists of two superimposed tubes of square section 63 and 64, between which is inserted a section 65 of rectangular section; the tubes 63 and 64 as well as the profile 65 are bent so as to match the curvature of the section part and have a length equal to the length of this section part. The square section tubes 63 are placed on beads 66 placed between the joining means and are fixed to the formwork plates 23 by screws 67 (see also Fig. 15).

Tie rods 68 parallel to the axis of the section pass through the profiles 65 and connect the two end faces of a section part.

Plates 69 are finally fixed to the square section tubes 63 and 64 by screws 70 and carry elastomer seals 71 ensuring good pressure distribution along the periphery of the formwork sections, and also allowing relative movement in the radial direction. between two sections 1 assembled end to end. The thickness of these joints is determined by the extent of the relative displacements of two successive sections.

The plates 69 have a notch intended to receive a rubber seal 72, the aim of which is to avoid losses of laitance during concreting, by infiltration towards the outside of the tunnel between the sections 1 assembled end to end.

Fig. 15 is a section through two wall sections 1 assembled end to end, and shows in section, the assembly of the end faces as well as the connection between two successive sections 1. This section is made along a plane passing through the plane of symmetry of a main element 22, perpendicular to its formwork plate 23.

Two sections of formwork 1 are assembled end to end by the assembly means generally designated by the reference 73 in FIG. 16. Fig. 16 is a section through two wall sections 1 assembled end to end; this section is made along a plane passing through a tie rod 67 and perpendicular to the formwork surface.

As can be seen, the assembly means is a toggle fastener comprising two claws 74 and 75 articulated to a body 76; the ends of each claw 74 and 75 are engaged under the flats 59 of the two sections, the body 76 being perpendicular to the claws 74, 75; the body 76 is then folded down along one of the sections by means of a lever 77 secured to the body 76, which has the effect of crossing the joints and bringing the ends of the claws 74, 75 towards each other, thereby clamping the sections axially to one another.

As can be seen in Figs. 15 and 16, the plates 69 of the end face of a section which carry the elastomeric seals 71 and the rubber seals 72, are applied against plates 78 with a flat surface fixed to the end face of the next wall section, which allows the relative displacements of the two end faces.

Claims (20)

1.- Formwork and shielding wall, formed by the end-to-end assembly of sections by their end faces, each section comprising at least one arcuate part whose generatrix is parallel to the axis of the section, each section being consisting of at least two section parts assembled together end to end, so that the assembly edges are parallel to the axis of the section, and by at least one key interposed between the surfaces of the ends of two parts of facing section, characterized in that each section portion is itself made up of a certain number of identical main elements (7, 19, 22) and, at each of its ends, of an end element (8, 9), and of means connection and blocking (10), each main element (7, 19, 22) comprises a substantially rectangular formwork plate (14, 23), one face of which constitutes the formwork surface (13), and a stiffening core (17, 20, 25) spaced from the formwork plate (14, 23) and located on the side of the face opposite to the formwork surface and rigidly connected to the formwork plate (14, 23), said plate (14, 23) being provided along two edges parallel to each other and to the axis of the section of joining means with the edge of the neighboring plates (14, 23), the said joining means constituting an articulation around an axis running along the assembled edges, each end element (8, 9) also comprises a substantially rectangular formwork plate (29, 30), one face of which forms the formwork surface, and a stiffening plate (31, 32) separated from the formwork plate (29, 30) and located on the side of the face opposite to the formwork surface and rigidly connected to the formwork plate (29, 30) by a core (39), each end element (8, 9) is attached to the formwork plate (14, 23) of the last main element (7, 19, 22) of a section portion by a joining means and, on the free end side , it is profiled, so as to allow the connection and the attachment with the end element (8, 9) of another part of the section, the connecting and blocking means (10) connect the cores (17, 20, 25) and the stiffening plates (31, 32) so as to keep all the elements locked in a determined position, with respect to each other (7, 19, 22, 8, 9) of the same section portion, the key (6) has a formwork surface (40) and two lateral insertion surfaces (43, 44), and the end elements (8, 9) adjacent to the key (6) are provided with means of assembly (11, 12) with the key (6) and compatible with the lateral insertion surfaces (43, 44) thereof, so as to allow the insertion of the key (6) with the formwork surface ( 40) forward. 2.- wall according to claim 1, characterized in that the joining means connecting the formwork plates (14, 23) of the main elements (7, 19, 22) to each other and with the formwork plates (29, 30) of the end elements (8, 9) of a same section portion comprise, on the one hand, a solid cylindrical knot (15) and, on the other hand, the hollow cylindrical imprint (16) of the same knot (15), the assembly between formwork plates (14, 23, 29, 30) of two elements (7, 19, 22, 8, 9) neighbors being made by interlocking a knot (15) of an element (7, 19, 22, 8, 9) in the indentation (16) of a neighboring element (7, 19, 22, 8, 9), in a direction parallel to the axis of the section. 3.- wall according to claim 2, characterized in that the formwork plate (14, 23) of a main element (7, 19, 22) carries, along one of two parallel edges, a solid cylindrical knot (15) and, along the other edge, the hollow cylindrical imprint (16) of the same node. 4.- wall according to any one of the preceding claims, characterized in that the stiffening core (17, 20, 25) is connected to the formwork plate (14, 23) by means of two connecting elements arranged in a V . 5.- wall according to claim 4, characterized in that said connecting elements arranged in V are sails (18, 26) full. 6.- wall according to claim 4, characterized in that said elements arranged in V are reticular structures. 7.- wall according to claim 4, characterized in that the connecting elements and the stiffening core (17, 20, 25) form an integral V-shaped structure (24). 8.- wall according to claim 7, characterized in that the formwork plate (23) carries, on its face opposite to the formwork surface, two parallel ribs provided, along their free edge, with a solid cylindrical knot (27), and the free edge of each of the elements connection of the integral V-shaped structure (24) is provided with a hollow imprint (28) of said node (27), the nesting of said two nodes (27) in said imprints (28) allowing the assembly of a main element (22). 9.- wall according to claim 7, characterized in that the formwork plate (14) is connected to the integral V-shaped structure (24) by welding. 10.- wall according to claim 7, characterized in that the formwork plate (14) is connected to the integral V-shaped structure (24) by gluing. 11.- wall according to any one of the preceding claims, characterized in that the stiffening core (17, 20, 25) has a longitudinal groove (21) in the form of a groove. 12.- wall according to any one of the preceding claims, characterized in that the end elements (8, 9) are profiled so as to allow hooking between them, in the direction towards the formwork surfaces, to the times along the edge of the formwork plate (29, 30), and along the edge of the stiffening plate (31, 32). 13.- wall according to claim 12, characterized in that for one of the end elements (9), the hooking means along the edge of the formwork plate (29) consists of a rib (36) provided with a flange (37), and the hooking means along the edge of the stiffening plate (31) consists of a notch (38), and for the other end element (8), the hooking means along the edge of the formwork plate (30) consists of a notch (38) intended to receive the flange (37) of the first end element (9), and the hooking means along the edge of the plate stiffening (32) consists of a rib (36) provided with a flange (37) intended to be engaged in the notch (38) of the first end element (9). 14.- wall according to claim 13, characterized in that each of the end elements (8, 9) consists of the same profile (33) comprising two plates (29, 30) connected by a core (39) perpendicular thereto, one of which constitutes the plate formwork (29, 30) and the other of which is assembled with a complementary connecting plate (34, 35) to form the stiffening plate (31, 32), the two plates (29, 30) having, along their edges located on the side of the main element (7, 19, 22), one, a solid longitudinal knot (15) and the other, the hollow imprint (16) of the same knot (15), the two plates (29, 30) having, moreover, on the side of the attachment of the elements (8, 9) between them, one, a rib (36) provided with a flange (37), and, l 'other, a notch (38), the said profile (33) thus allowing indifferently, by turning it 180 °, both the assembly with a formwork plate (14, 23) of a main element having an imprint (16) or a knot (15) and the attachment of two end elements (8, 9) between them. 15.- wall according to any one of the preceding claims, characterized in that the key (6) consists of a main element (7, 19, 22) and two end elements (8, 9), bearing each a plate (45) one face of which constitutes the sliding surface (43, 44) allowing the insertion of the key (6), each plate (45) being connected to the end element (8, 9) the closer by an intermediate plate (53), one of the faces of which is provided with means for hooking to this end element (8, 9). 16.- wall according to any one of the preceding claims, characterized in that the assembly means (11, 12) of the end elements (8, 9) with the key (6) each consist of a plate (45) of which one face constitutes a sliding surface (41, 42) compatible with one of the sliding surfaces (43, 44) of the key (6), and of an intermediate plate (53) allowing the attachment with the 'nearest end element (8, 9). 17.- wall according to any one of the preceding claims, characterized in that the main elements (7, 19, 22), the end elements (8, 9) and the assembly means (11, 12) are made of metal. 18.- wall according to any one of claims 1 to 16, characterized in that the main elements (7, 19, 22), the end elements (8, 9) as well as the assembly means (11, 12) are made of polymeric materials. 19.- wall according to claim 18, characterized in that the main elements (7, 19, 22), the end elements (8, 9) and the assembly means (11, 12) are made of materials reinforced polymers. 20.- wall according to any one of claims 1 to 16, characterized in that the main elements (7, 19, 22), the end elements (8, 9) as well as the assembly means (11, 12) are made of fiber cement.

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